1. Field of Invention
The invention discloses a scanner and, in particular, a scanner installed with a movable reflecting surface module on a transparent platform for scanning both transparent and reflective documents.
2. Description of the Prior Art
Please refer to FIG. 1 and FIG. 2. FIG. 1 is a perspective view of a conventional scanner 10. FIG. 2 is a functional block diagram of the scanner 10. The scanner 10 comprises a casing 12 with a transparent platform 14 onto which is placed a document to be scanned, a scanning module 16, a driving device 18 installed inside the casing 12 for moving the scanning module 16, and a control circuit 20 installed inside the casing 12 for controlling operations of the scanner 10.
The scanning module 16 is movably installed underneath the transparent platform 14 and comprises a light source 22 for illuminating the document on the transparent platform 14, an image sensing module 24 to scan images from the document on the transparent platform 14 to produce corresponding scanning signals, and a reflector module 28 to reflect light from the document to the image sensing module 24. The scanner 10 further comprises a reflecting surface module 26 installed on the transparent platform 14 to reflect light emitted from the light source 22 down to the transparent platform 14.
Please refer to FIG. 3, which is a cross-sectional view of the scanner 10 in FIG. 1 along line 3xe2x80x943. The reflecting surface module 26 includes a first reflector 23 and a second reflector 25, both being installed on either side of the upper portion of the light source 22. The first reflector 23 reflects light emitted upwardly from the right side of the light source 22 horizontally to the second reflector 25, which then reflects the light down to the transparent platform 14.
When a user wishes to scan a transparent document 13, the user must place the reflecting surface module 26 on the transparent platform 14 so that the light emitted from the right side of the light source 22 will pass down through the document 13 via the first reflector 23 and the second reflector 25. Reflected by the reflector module 26, the light is sent to the image sensing module 24 to produce corresponding image signals. The reflecting surface module 26 is unremovably installed on the transparent platform 14.
The scanner 10 further comprises an upper cover (not shown). When a user wishes to scan a reflective document, the user can take off the reflecting surface module 26 and put on the upper cover. Light emitted from the light source 22 upwardly will reflect down off the document 13. Through the reflector module 28, the light is then reflected to the image sensing module 24 to produce corresponding image signals.
When the scanner 10 scans a transparent document, the light upwardly emitted from the light source 22 must be reflected by the first reflector 23 and the second reflector 25 to pass downward through the transparent document. The scanning area cannot be larger than the reflecting surface module 26, and is limited by the sizes of the first reflector 23 and the second reflector 25. Larger first and second reflectors 23 and 25 cover more area over the transparent platform 14, permitting larger documents to be scanned.
To increase the scanning area for transparent documents in the scanner 10, the area and height of the reflecting surface module 26 has to be increased correspondingly. As the area of the reflecting surface module 26 gets larger, the document area covered by the reflecting surface module 26 also becomes larger. As the reflecting surface module 26 gets higher, the area for installing the first reflector 23 and the second reflector 26 gets larger. Thus, the scanning area for transparent documents in the scanner 10 becomes larger.
Increasing the area and height of the reflecting surface module 26 increases the volume thereof. This does not only increase the manufacturing cost of the scanner 10 but also makes the use of the scanner 10 inconvenient.
Furthermore, as shown in FIG. 3, since the document 13 and the transparent platform 14 are not totally transparent, when scanning a transparent document the light emitted from the left side of the light source 22 will be partially downwardly reflected and absorbed by the image sensing module 24. The image signal noise is thus increased, lowering the scanning quality.
It is thus a primary objective of the present invention to provide a scanner with a reflecting surface module movably installed on a transparent platform for solving the aforementioned problems of the prior art.
Briefly, the present invention discloses a scanner with a casing having a transparent surface, a scanning module, a reflecting surface module, a driving device and a control circuit. A document to be scanned is placed on the transparent surface of the casing. The scanning module is moveably installed inside the casing under the transparent surface, and is used to scan the document and produce corresponding scanning signals. The scanning module has a light source installed under the transparent surface to illuminate the document, an image sensing module to scan images from the document and produce the corresponding scanning signals, and a reflective module to reflect the images from the document to the image sensing module. The reflecting surface module is moveably installed above the transparent surface, and is used to reflect light from the light source down to the transparent surface. The driving device is installed inside the casing to move the scanning module. The control circuit controls the operations of the scanner. The reflecting surface module moves synchronously along a predetermined direction following the scanning module to scan the document on the transparent platform. If the document is predominantly transparent, light emitted upwardly from the light source passes through the document, is reflected downward to the transparent platform by the reflecting surface module, and is then reflected by the reflective module to the image sensing module to produce the corresponding scanning signals. If the document is predominantly reflective, then light from the light source is reflected downward from the document to the image sensing module by the reflective module to produce the corresponding scanning signals.
It is an advantage of the present invention that, because the reflecting surface module moves with the scanning module, the scanning area is not limited by the areas of the mirrors in the reflecting surface module. Hence, the size of the reflecting surface module is greatly reduced. Additionally, the present invention helps to reduce the amount of noise caused by unwanted reflected light, thus improving image quality.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings.